What is ASP.NET Core?

What is ASP.NET Core?

ASP.NET Core is a free, open-source, cross-platform framework for building modern, cloud-based, internet-connected applications. It's the web framework built on top of .NET that powers everything from simple websites to complex enterprise applications.

What Can You Build?

• Web APIs: RESTful services for mobile apps, SPAs, and microservices
• MVC Web Apps: Traditional server-rendered web applications
• Razor Pages: Page-focused web apps (simpler than MVC)
• Blazor Apps: Interactive web UIs using C# instead of JavaScript
• Real-Time Apps: SignalR for WebSockets and real-time communication
• gRPC Services: High-performance RPC framework
• Microservices: Distributed, containerized services

A Brief History

ASP.NET Framework (2002-2016)

The original ASP.NET was released in 2002 as part of the .NET Framework. It was revolutionary for its time but had limitations:

• Windows-only (tied to IIS)
• Monolithic architecture
• Slow release cycles
• Heavy memory footprint
• Tightly coupled to System.Web.dll

ASP.NET Core (2016-Present)

In 2016, Microsoft released ASP.NET Core—a complete rewrite from the ground up. It addressed all the limitations of the old framework:

ASP.NET Framework	ASP.NET Core
Windows-only	Cross-platform (Windows, macOS, Linux)
IIS-dependent	Self-hosted or IIS/Nginx/Apache
Monolithic	Modular (install only what you need)
Slow	Extremely fast (top TechEmpower benchmarks)
Closed source	Open source (GitHub)
Infrequent updates	Regular releases (yearly LTS)

Key Features and Benefits

1. Cross-Platform

Develop on Windows, macOS, or Linux. Deploy to Windows Server, Linux, Docker containers, or cloud platforms (Azure, AWS, Google Cloud).

# Develop on Windows
dotnet new webapi -n InvenTrack.Api
dotnet run

# Deploy to Linux Docker container
docker build -t inventtrack-api .
docker run -p 8080:80 inventtrack-api

2. High Performance

ASP.NET Core consistently ranks among the fastest web frameworks in the world. It's optimized for:

• Minimal memory allocation
• Efficient HTTP parsing
• Asynchronous I/O by default
• Response caching and compression
• Kestrel web server (extremely fast)

3. Built-in Dependency Injection

ASP.NET Core has dependency injection (DI) built into its core. This makes your code:

• More testable
• More maintainable
• Loosely coupled
• Following SOLID principles

// Register service
builder.Services.AddScoped<IProductService, ProductService>();

// Inject into controller
public class ProductsController : ControllerBase
{
    private readonly IProductService _productService;
    
    public ProductsController(IProductService productService)
    {
        _productService = productService;
    }
}

4. Middleware Pipeline

ASP.NET Core uses a middleware pipeline to process HTTP requests. Each middleware component can:

• Handle the request and return a response
• Process the request and pass it to the next middleware
• Process the response on the way back

Request → [Authentication] → [Routing] → [Authorization] → [Endpoint] → Response
          ↓              ↓             ↓              ↓            ↓
       Logging      CORS Check    Rate Limit    Controller   JSON Result

5. Unified Programming Model

Whether you're building a Web API, MVC app, or Razor Pages site, you use the same:

• Configuration system
• Dependency injection
• Middleware pipeline
• Logging framework
• Hosting model

6. Cloud-Ready

ASP.NET Core is designed for cloud deployment:

• Environment-based configuration
• Health checks
• Distributed caching
• Containerization support (Docker)
• Azure integration (App Service, Functions, etc.)

ASP.NET Core Architecture

The Request Pipeline

Every HTTP request flows through ASP.NET Core like this:

1. HTTP Request arrives
   ↓
2. Kestrel web server receives it
   ↓
3. Middleware pipeline processes it
   ↓
4. Routing determines which endpoint to call
   ↓
5. Controller/Endpoint executes
   ↓
6. Response is generated
   ↓
7. Middleware processes response (reverse order)
   ↓
8. HTTP Response sent back to client

Key Components

Component	Purpose
Kestrel	Cross-platform web server
Middleware	Request/response processing pipeline
Routing	Maps URLs to endpoints
Controllers	Handle requests and return responses
Model Binding	Maps request data to C# objects
Validation	Validates input data
Filters	Cross-cutting concerns (auth, logging, etc.)

Application Types in Detail

Web API (RESTful Services)

Perfect for building backend services that serve JSON/XML data to clients.

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    [HttpGet]
    public ActionResult<IEnumerable<Product>> GetProducts()
    {
        return Ok(products);
    }
}

Use for: InvenTrack API, mobile backends, microservices

MVC (Model-View-Controller)

Traditional server-rendered web applications with separation of concerns.

Use for: Admin dashboards, content management systems

Razor Pages

Page-focused model, simpler than MVC for page-centric scenarios.

Use for: Simple websites, forms, CRUD operations

Blazor

Build interactive web UIs using C# instead of JavaScript. Runs in the browser via WebAssembly or on the server.

Use for: Rich, interactive web applications without JavaScript

Why ASP.NET Core for InvenTrack?

Requirement	How ASP.NET Core Delivers
RESTful API	Built-in Web API support with automatic JSON serialization
Database Access	Entity Framework Core integration
Authentication	ASP.NET Core Identity + JWT support
Validation	Model validation with Data Annotations or FluentValidation
Logging	Built-in logging framework, Serilog integration
Performance	Handle thousands of concurrent users
Scalability	Stateless design, easy to scale horizontally
Deployment	Docker, Azure, AWS, on-premises—deploy anywhere

Comparison with Other Frameworks

Framework	Language	Performance	Type Safety	Ecosystem
ASP.NET Core	C#	⭐⭐⭐⭐⭐	Strong	Excellent
Node.js/Express	JavaScript	⭐⭐⭐	Weak (TypeScript helps)	Massive
Spring Boot	Java	⭐⭐⭐⭐	Strong	Excellent
Django	Python	⭐⭐⭐	Weak	Good
Ruby on Rails	Ruby	⭐⭐	Weak	Good

Key Takeaways

• ASP.NET Core is a cross-platform web framework built on .NET
• It's a complete rewrite of the old ASP.NET Framework
• Cross-platform: Windows, macOS, Linux
• High performance: Top-tier in benchmarks
• Open source: Community-driven on GitHub
• Build Web APIs, MVC apps, Razor Pages, Blazor, and more
• Built-in DI: Dependency injection out of the box
• Middleware pipeline: Flexible request processing
• Cloud-ready: Designed for modern deployment
• Perfect for InvenTrack: RESTful API with EF Core, Identity, and more
• Powers enterprise applications at massive scale